Loud-speaker system for drive-in theaters



June 19, 1951 E. B. BRADY 2,557,408

LOUD-SPEAKER SYSTEM FOR DRIVE-IN THEATERS Filed S ept. 28, 1948 F 4 I B i a E 3 1? 1W 'mmvrox. I fbw/wa' 5 ERADY drive/vars speaker station of a drive-in theatre.

Patented June 19, 1951' LOUD-SPEAKER SYSTEM FOR DRIVE-IN THEATERS Edward B. Brady, Cleveland, Ohio Application September 28, 1948, Serial No. 51,592

3 Claims 1 The present invention relates to drive-in theatres equipped with in-car speakers and, more particularly, to a talk-back system permitting communication between the customers and the concession stand, which system utilizes the in-car speaker units.

Prior to the present invention, it was customary for the customers of drive-in theatres if they desired any refreshments, to leave their cars and walk to the concession stand which, in some instances, was three hundred feet or more away. This naturally inconvenienced the customers and was not conducive to maximum concession stand sales.

The principal object of the invention is the provision of a talk-back system for drive-in theatre equipment with in-car speakers, which system permits the customers to communicate with the concession stand, and is simple in construction, inexpensive to install and operate and utilizes the in-car speaker units.

The invention resides in certain constructions and combinations and arrangements of parts and further objects and advantages will be apparent to those skilled in the art to which it relates from the following description of the preferred embodiment described with reference to the accompanying drawings forming a part of this specification, in which Fig. 1 is a perspective view of a customers in-car speaker station of a drive-in theatre equipped with the present invention; and

Fig. 2 is a fragmentary, schematic wiring diagram of a drive-in theatre equipped with an incar speaker and concession stand talk-back system of the present invention.

Referring to the drawings, the reference character A designates generally a customers in-car The station shown comprises two portable in-car speaker units H], H detachably connected to opposite sides of a bracket 12 forming the cover of a junction box [3 on the top of a hollow iron pole I 4 projecting from the ground in the center of a car ramp. Each of the speaker units H), H is electrically connected to the junction box I3 by a four-conductor cable l5 of some suitable length, usually about six feet. The stations A are so located along the various car ramps of the theatre that there is one such station for each two customer cars. The customers drive their cars up alongside of the stations A, reach out and remove the speaker units from their supports and hang them in their cars. The

sound reproduced from the film being projected =5 is fed from the projection booth to the in-car speaker units by means of underground cables extending from the projection booth to the junction boxes I 3. a

The reference characters Bl, B2, B3, B4, B5,

B6 shown in Fig. 2 represent two wire buses connected to and leading from the output of the sound amplifier, designated generally by the reference character 20, in the projection booth P, which amplifier may be of any desired wellknown construction. While only six buses are shown, it is to be understood that any desired number of buses may be provided. Each bus is preferably in the form of a two-conductor,

underground cable and extends along one or more of the car ramps of the theatre. At each of the stations A the buses are connected to a transformer 2| common to the two in-car speaker units In, H at that particular station. The primaries 22 of all of the transformers 2! con nected to any one bus are connected in parallel with the bus conductors 23, 24. I The secondary 25 of the transformer 2| located at any station A is connected in parallel circuit by conductors Z6, 21 with two potentiometers 30, 3|, one located in each of the in-car speaker units H], II, which potentiometers-provide means whereby the customer may control the volume of the particular speaker with which it is associated. In addition to being connected to the potentiometers 3B, 3! in the respective in-car speaker unit, the conductor 2! is connected to contacts 32, 33 of push button switches 34, 35 located in the in-car speaker units 18, M, respectively. The other contacts 36, 3! with which the contacts 32, 33 are associated and with which they are normally connected, are connected to speakers or speaker elements 40, 4| by wires 42, 43. The movable contact arms 44, 45 of the potentiometers 30, 3i are connected by wires 46, 41 to contacts 50, 5! of the switches 34, 35, which contacts are normally connected to contacts 52, 53, which latter contacts are, in turn, connected to the speakers 40, 4| by wires 54, 55.

. The wires 42, 54 and 43, 55 connected to the push button switches 34, 35 are depressed are connected by means of wires 66, 61. to conductors 10, ll of a two-wire bus CI, which bus is simiswitches of each of the in-car speaker units are. accessible from the outside of the speaker unit case and when a customer wishes'to communicate with the concession stand, he merely depresses the push button switch associated with his incar speaker unit, thereby connecting his speaker to the concession stand, which speaker may thereafter be used both as a speaker and a microphone.

At the concession stand the conductors I0, II ofbus CI are connected to a two-conductor bus comprising the conductors 12', I3 as are the other buses '02 to C6, etc., extending along one or more of the other ramps of the theatre. The ramp buses BI, etc., and CI, etc., may be shielded, if desired, and are preferably underground. The conductors I2, I3 are adapted to be selectively connected by a push button or other suitable switch I4, either to the input circuit or to the 'output circuit of a power amplifier in the concession stand, designated generally by the reference character 15. The amplifier 15 may be of any conventional construction. A speaker 16 also in the concession stand is adapted to be selectively connected by the switch 14 simultaneously to the opposite side of' the amplifier from that to which the conductors I2, I3 are connected so that the speaker 16- may be used either as a speaker or'a microphone by the concession stand operator.

Normally the wires 12; 13' are connected to-the input circuit of the amplifier I5 and the speaker 16 to the output circuit thereof so that when one of the customers depresses the'push button switch associated with his in-car speaker, he can talk to the concession stand. The concession stand operator can then talk to the customer if he maintains 'hispush button switch in depressed position by depressing the push button switch "H "in the concession-stand.

The icbnductors I2, 13, as-shown, are connected to contacts 80, 81 of switch M, which contacts are normally connected to contacts 82, '83. The contacts 82, '83 are connectedby conductors 84, 85 to the input circuit of the amplifier I5. The output circuit of the amplifier is connected by conductors 86, 81 tocontacts 90, 9| and'92, 93, respectively, of push button switch 14. The contacts 90', 02 are normally connected to contacts 84, 85 connected by'conductors 9B, S'Ito theconcession stand speaker 16, thereby completing the "circuit from the in-car speaker unitsthrough the conductors 12, I3 and the amplifier "IS' t'o'the concession stand speaker 16. When the concession stand operator wishes to answer the=cus- "tomer,:he depresses push'button switch T4 connecting his speaker '16 to the input circuit of the amplifier IS-through the normally open contacts I00, IOI and I02, I03, which contacts close upon the pushbutton switch Mbeingdepressed. "The concession stand speaker 16' issimultaneously disconnected 'from the output circuit off-the amiplifier '15 bythe opening of normally closedrcon- :tacts"90, 94 and 92, '95. Atthesame time-that the input circuit of the amplifier 15, the customers speaker is connected to the output circuit of the amplifier by the closing of normally open contacts 9|, I56 and 93, I05, the contacts I04, I05 being connected to the conductors 12, I3 of the concession stand bus.

It is believed that the operation of the device will be apparent from the foregoing description thereof. Suffice it to say that any customer can communicate with the concession stand by depressing the push button switch at his in-car speaker unit and upon the switch it in the concession'stand being properly manipulated by the concession stand operator. As a practical matter,

. thev number of customer stations A that can be connected to any one amplifier and speaker combination in a concession stand is limited but the number of customer stations connected to any one amplifier and speaker unit can be kept within practical limitations by providing a plurality of separate channels or circuits, each connected to a limited number of customer stations and each having its own amplifier and speaker combination.

From the foregoing description of the preferred embodiment of the invention, it will be apparent that the objects heretofore enumerated and others have been accomplished and that there has been provided a novel and improved in-car speaker system for theatres incorporating a talkback system whereby the customers may talk to the concession stand and which system requires a minimum of additional equipment and utilizes the speaker element of the in-car speaker unit both as a microphone and as a speaker for the talk-back system. While the preferred embodiment of the invention has been described in considerable detail, it will be apparent that the invention is not limited to the particular construction shown and it is my intention to cover hereby all adaptations, modifications and uses thereof which come within the practice of those skilled in the art to which the invention relates and within the scope of the appended claims.

Having thus described my invention, I claim:

1. In an in-car speaker system for a drive-intheatre having a concession stand, a program sound amplifier and an in-car speaker unit connected with the output circuit or said amplifier, an'amplifier and a speaker unit at the concession stand, a circuit connecting said in-car speaker unit with said amplifier and speaker unit at said concession stand, switching means at said incar speaker unit for connecting said in-car speaker unit with one or the other of said circuits, switching means including an actuating member at said concession stand adapted to connect said concession speaker unit with the concession amplifier output and the second mentioned circuit with the concession amplifier input when said actuating member is in one positionand to connect said concession speaker unit with the concession amplifier input and said secondmentioned circuit with said concession amplifier output when said actuating member is .moved to a second position.

2. Inan in-car speaker system for a drive-intheatre having a concession stand, a program ,soundamplifier. and. a plurality of in-car speaker .units connected in parallel with the output cir- .cuit of saidamplifier, an amplifier and a speaker 'unit atithe concession stand, a circuit connecting said'in-car-speaker units with said conces- .flramoncessionstand'ispeaker 16. isiconnectedflto s-i0n-:stand-:amp1ifie1 unit, switching means at each of said in-car speaker units for connecting the respective in-car speaker units with one or the other of said circuits, switching means including an actuating member at said concession stand adapted to connect said concession speaker unit with the concession amplifier output and the second mentioned circuit with the concession amplifier input when said actuating member is in one position and to connect said concession speaker unit with the concession amplifier input and said second mentioned circuit with said concession amplifier output when said actuating member is moved to a second position.

3. In an in-car speaker system for a drive-intheatre having a concession stand, a program sound amplifier and an in-car speaker unit connected with the output circuit of said amplifier, an amplifier and a speaker unit in the concession stand, a circuit connecting said in-car speaker unit and said concession stand amplifier unit, switching means at said in-car speaker unit normally positioned to connect said in-car speaker unit with said output circuit and mov- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,054,933 Frazier Sept. 22, 1936 2,396,756 Snodgrass Mar. 19, 1946 2,463,339 Wetzel et a1 Mar. 1, 1949 

